A 13-year-old child’s vision of 4.9 is not normal. Consider pseudomyopia, mild true myopia or eye diseases. 1. Pseudomyopia: 13-year-old children just in the middle school stage, this stage of heavy learning tasks, if long-term reading, writing, using electronic products, etc., will lead to visual fatigue, blurred vision, eye pain, eye fatigue and other symptoms, dilated optometry myopia disappeared, can be diagnosed as pseudomyopia, can be reversed after improving the habits of eye use. 2. Mild true myopia: 13-year-old children with normal visual acuity of 5.0, visual acuity of 4.9, myopia does not disappear after dilated optometry, can be diagnosed as true myopia, but usually belongs to the mild true myopia, you can follow the doctor’s orders to wear glasses to adjust the treatment. 3. Eye diseases: Eye diseases, such as optic neuritis, may lead to vision loss and require treatment for the primary cause. In addition to the above reasons, farsightedness, astigmatism, etc. may also lead to vision loss in children. For a 13-year-old child with a visual acuity of 4.9, parents should take their children to an ophthalmologist in time for a systematic checkup, and then follow the doctor’s instructions for correction or treatment.